1. Field
Embodiments of the present disclosure relate to a washing machine capable of reducing noise by performing a zero-current control during braking of a motor, and a control method thereof.
2. Description of the Related Art
In general, a washing machine (for example, drum washing machine) is an apparatus including a tub to store water (for example, wash water or rinse water), a drum rotatably installed in the tub to accommodate laundry, and a motor to generate a driving force to rotate the drum. When the cylindrical drum rotates, the laundry in the drum is washed through motion of rising and falling along the inner wall of the drum.
Such a washing machine carries out washing in a series of operations of a washing cycle to separate contaminants from laundry with water (specifically, wash water) with detergent dissolved therein, a rinsing cycle to rinse the laundry with water (specifically, rinse water) with no detergent to remove bubbles or residual detergent from the laundry, and a spin-drying cycle to remove moisture contained in the laundry by high-speed rotation of the drum. When the drum is rotated in an imbalanced state with the laundry not distributed uniformly in the drum while washing proceeds in such a series of operations, a biased force is applied to a rotation shaft of the drum so that the washing tub makes eccentric motion, thereby causing vibration of the tub. Such vibration of the tub becomes more severe when the drum rotates at high speed for the spin-drying cycle.
In the convention technology, a vibration sensor to measure the vibration of the tub is fixedly attached to an upper portion of the tub to detect the vibration of the tub generated due to uneven distribution of the laundry. In this manner, the vibration of the tub is detected by the vibration sensor, and if an excessive vibration is generated during a spin-drying cycle, the motor is put to a braking to stop the spin-drying cycle, and water is supplied again to proceed with a laundry disentanglement cycle, and then a spin-dry cycle retry operation is performed to return to the spin-dry cycle.
At this time, in order to brake the motor, a short brake method is used in which a switching device at a lower end of an inverter is turned on, and a switching device at an upper end of the inverter is turned off.
However, the short brake method is configured in which a large amount of current flows at the motor, causing noise during the braking. In particular, a belt-type brushless direct current (BLDC) motor, with noise of a belt added, causes great noise during the brake after a weight detection (sudden acceleration).
When a vibration sensor is fixedly attached to the tub in a normal manner, the vibration of the tub is not detected and the excessive vibration is not detected during the spin-drying cycle, and thus the washing machine may be moved or a frame touch may occur.